A known signal relay connector has a daughterboard with a first edge having a plurality of first connection pads arranged thereon and a second edge having a plurality of second connection pads arranged thereon. The daughterboard has printed wiring for connecting a first connection pad with a second connection pad. Thus, in the signal relay connector, a signal sent and/or received between a first circuit connected to the first edge and a second circuit connected to the second edge is relayed.
Japanese Patent Application No. 2004-523087A discloses an electrical connector assembly serving as such a signal relay connector. The electrical connector assembly has a circuit board equivalent to the daughterboard, a plurality of first connection pads arranged at a lower end edge of the circuit board, and a plurality of second connection pads arranged at a side end edge extending vertically on the circuit board. The electrical connector assembly also has contacts contacting the first connection pads. The periphery of the circuit board is substantially completely enclosed with a housing to constitute the electrical connector assembly. The electrical connector assembly, in its integrally assembled state, has the contacts connected to a motherboard by press-fitting.
Signals relayed by connectors have increasing speed in modern applications. As the speed of the signal increases, the daughterboard inside the connector also frequently generates heat. Lowering the temperature of the connector is a critical issue in maintaining proper functioning of the connector. In the electrical connector assembly of JP 2004-523087A, the periphery of the daughterboard is substantially completely covered with the housing; the electrical connector assembly has a structure allowing very little air to be exchanged between inside and outside. For this reason, in the electrical connector assembly of JP 2004-523087A, the heat generated at the daughterboard accumulates inside the housing, which causes the temperature of the electrical connector assembly to increase.